How high is "high-IQ" and how low is "low IQ" in your book?

Someone with an above-average IQ of 115-120, like your average undergrad, visibly struggles with 101 / 201 level work and is deeply resistant to higher-level concepts. Actually getting through grad school takes about a 130 as previously mentioned, and notable scientists tend to be in the 150+ range. So somewhere from 84-98% of the population is disqualified right off the bat, with only the top 2-0.04% capable of doing really valuable work.

And that's assuming that IQ is the only thing that counts; in actuality, at least in the hard sciences, there is an enormous amount of technical knowledge and skill that a person has to learn to provide real insight. I cannot think of a single example in the last 50 years which fits your narrative of the smart outsider coming in and overturning a well-established scientific principle, although I would love to hear of one if you know any.

No, I don't want laymen to trust in a process they cannot understand.

So no more trusting chemotherapy to treat your cancer? The internet to download your music, or your iPod to play it? A fixed wing aircraft to transport you safely across the Atlantic? Must be tough even just driving to work, now that your car is mostly computer-controlled and made of materials with names that sound like alphabet soup.

Almost every aspect of modern life, even for a polymathic genius, is going to be at least partially mysterious; the world of our tools and knowledge is far too complex for the human mind to fully grasp.